[v3,15/20] coresight: tmc-etr: Introduce the notion of reference counting to ETR devices
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Message ID 20190404033541.14072-16-mathieu.poirier@linaro.org
State In Next
Commit b537277c1787e205e15db15be5c96bc2f1234f06
Headers show
Series
  • coresight: Add support for CPU-wide trace scenarios
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Commit Message

Mathieu Poirier April 4, 2019, 3:35 a.m. UTC
This patch adds reference counting to struct etr_buf so that, in CPU-wide
trace scenarios, shared buffers can be disposed of when no longer used.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 5 +++++
 drivers/hwtracing/coresight/coresight-tmc.h     | 3 +++
 2 files changed, 8 insertions(+)

Patch
diff mbox series

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index e1774d4bb5f3..1346474ac019 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -8,6 +8,7 @@ 
 #include <linux/coresight.h>
 #include <linux/dma-mapping.h>
 #include <linux/iommu.h>
+#include <linux/refcount.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/vmalloc.h>
@@ -1221,7 +1222,11 @@  get_perf_etr_buf_per_thread(struct tmc_drvdata *drvdata,
 	 * with memory allocation.
 	 */
 	etr_buf = alloc_etr_buf(drvdata, event, nr_pages, pages, snapshot);
+	if (IS_ERR(etr_buf))
+		goto out;
 
+	refcount_set(&etr_buf->refcount, 1);
+out:
 	return etr_buf;
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 487c53701e9c..ee44906dffe8 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -9,6 +9,7 @@ 
 
 #include <linux/dma-mapping.h>
 #include <linux/miscdevice.h>
+#include <linux/refcount.h>
 
 #define TMC_RSZ			0x004
 #define TMC_STS			0x00c
@@ -133,6 +134,7 @@  struct etr_buf_operations;
 
 /**
  * struct etr_buf - Details of the buffer used by ETR
+ * refcount	; Number of sources currently using this etr_buf.
  * @mode	: Mode of the ETR buffer, contiguous, Scatter Gather etc.
  * @full	: Trace data overflow
  * @size	: Size of the buffer.
@@ -143,6 +145,7 @@  struct etr_buf_operations;
  * @private	: Backend specific information for the buf
  */
 struct etr_buf {
+	refcount_t			refcount;
 	enum etr_mode			mode;
 	bool				full;
 	ssize_t				size;